Four Radial Meander-line Top-loading Antenna for Parking Lot System

This letter presents an antenna for smart parking lot management systems. The antenna is installed on parking lot pavements in order to transmit signals at 868 MHz (wavelength λ = 345 mm) when a car enters a parking space. The proposed antenna has a meander-line top-loaded structure that can reduce the size of the horizontal radiating element and obtain a conical radiation characteristic. Impedance matching is achieved by removing the conductor around a feeding point. As a result, S
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is −17.78 dB at the center frequency, and the −10-dB bandwidth at 188 MHz is 2.16%. The diameter of the proposed antenna is 50 mm and its height is 13 mm. Thus, its volume is reduced by 90.57% compared with the general-plate top-loaded antenna, which has a diameter of 110 mm and height of 28.5 mm.